Transparent egg carton

ABSTRACT

The present invention provides an egg carton having a tray having a first row of a first plurality of spaced egg compartments and a second row of a second plurality of spaced egg compartments, the first row of egg compartments being disposed in parallel spaced relationship to the second row of egg compartments; a plurality of spaced tower elements extending along a centerline of the tray and extending vertically from a plane of the tray, each tower element having four egg contacting surfaces; a plurality of spaced post elements extending along a front edge of the tray and extending vertically from a plane of the tray, each post element having two egg contacting surfaces; and a lid hingedly connected along a rear edge of the tray and movable from an open condition to a closed condition.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention provides an egg carton and more particularly anegg carton of a transparent polymeric material.

2. Background of the Invention

Conventional egg cartons in wide use today are typically made either ofa fibrous material, such as cardboard, or a foamed polymeric material,such as foamed polystyrene. While these materials are inexpensive toprepare they share the same disadvantage of being opaque, requiring aconsumer to open the lid of the egg carton to inspect the eggs fordamage.

Egg cartons made of a transparent polymeric materials, such aspolyethylene terephthalate (PET) polymers have also come into use,although to a more limited extent than cardboard and foamed polystyrenecartons. Such transparent egg cartons exhibit various disadvantages thatresult from the properties of the materials used. For example, whilethese materials are recyclable, they are not biodegradable.

Transparent polymeric egg containers in the market today commonly havetwo lids in a trifold design. The first lid is conformed to fit over thetop of the eggs, and the second lid is conformed to fit over the firstlid. In another design, instead of using a flap, the lid and tray of thecarton are configured with a series of snap locks around the rim.Another egg carton disclosed in U.S. Pat. No. 4,240,575 shows a lockingflap and hinge at an obtuse angle so that the flap is situated in apartially closed position. However, this design does not eliminate theproblem of bending of the egg carton when grasped from the end.

One observation of some transparent egg cartons is it is difficult forconsumers to release the lid from the interlocking tabs and holes. Inthe cardboard or foamed polystyrene designs, the consumer typicallypulls the front of the lid forward from the center to clear the holesfrom the tabs and rotates the lid upward to open the carton. However, ifthe flap and lid are made of typical transparent polymeric materials,which are more pliable than cardboard or foamed polystyrene, pulling thefront surface of the lid forward from the middle creates a bow actionthat results in bowing of the middle of the flap outward and the lateralsides of the flap inward, making it difficult to release the lid fromthe button tabs on the flap. One method of overcoming this problem isexemplified by U.S. Pat. No. 4,463,894 where it is disclosed to make thelateral portions of the flap thicker than the central portion to reducethe bowing effect. A problem with this design is that more material isrequired to form the flap.

Commonly assigned U.S. Pat. No. 7,258,234 discloses a transparent eggcarton having a tray, a lid and a flap hingedly connected to a frontedge of the tray for securing the lid to the tray when in a closedcondition. The '234 patent discloses an egg carton formed fromtransparent plastic material such as polylactic acid or otherbiodegradable polymers. The flap is made with lattice struts to increasethe lateral strength of the flap and has three button tabs forinterlocking the flap to the lid.

Accordingly there is a need in the art to provide transparent eggcartons that have the advantages of cardboard and foamed polystyrene eggcartons while lacking the disadvantages inherent to cartons made oftransparent polymeric materials.

SUMMARY OF THE INVENTION

The present invention provides an egg carton having a tray having afirst row of a first plurality of spaced egg compartments and a secondrow of a second plurality of spaced egg compartments, the first row ofegg compartments being disposed in parallel spaced relationship to thesecond row of egg compartments; a plurality of spaced tower elementsextending along a centerline of the tray and extending vertically from aplane of the tray, each tower element having four egg contactingsurfaces; a plurality of spaced post elements extending along a frontedge of the tray and extending vertically from a plane of the tray, eachpost element having two egg contacting surfaces; and a lid hingedlyconnected along a rear edge of the tray and movable from an opencondition to a closed condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of an egg carton in anopen condition;

FIG. 2 is a perspective view of the egg carton of FIG. 1 in a closedcondition;

FIG. 3 is a top plan view of the egg carton of FIG. 1;

FIG. 4 is a side elevation view of the egg container of FIG. 1;

FIG. 5 is a bottom plan view of a tray of an egg carton;

FIG. 6 is a top plan view of a second embodiment of an egg carton;

FIG. 7 a is a side elevation view in cut away of the second embodimentof the egg carton of FIG. 6 in a closed condition; and

FIG. 7 b is a side elevation view in cut away of the second embodimentof the egg carton of FIG. 6 in an open condition.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiment in many differentforms, there is shown in the drawings, and will be described herein indetail, specific embodiments thereof with the understanding that thepresent disclosure is to be considered as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the specific embodiments illustrated.

Described herein are various features of a transparent egg carton 10,which is suitable for embodiments using a variety of transparentpolymeric materials, including, but not limited to relatively pliablerecyclable polymeric materials such as polyethylene terephthalate (PET),which is an amorphous polyester; clarified polypropylene (CPP), which ispolypropylene containing nucleating agents to increase clarity; styrenebutadiene copolymers (SBC) without impact modifiers; copolymer blends ofSBC with crystalline polystyrene (cPS), which is commercially known as“K-Resin/Crystal™”, oriented polystyrene (OPS); polyvinyl chloride(PVC); styrene acrylonitrile polymer (SAN); polymethyl methacrylate(PMM) and copolymers thereof, commercially known as Plexiglas; andpolycarbonate (PC). In advantageous embodiments, the features of the eggcarton 10 are also suitable for a newer class of transparent polymericmaterials that are recyclable and biodegradable. Examples of suchpolymeric materials include polylactic acid (PLA), polyglycolic acid(PGA) and polylactic acid-glycolic acid copolymers (PLGA). In apreferred form of the invention, the egg carton 10 is preferably made ofPLA, PGA, or PLGA in commonly known polymeric processing techniques suchas thermoforming, injection molding, vacuum forming or other techniqueswell known to those skilled in the art.

FIG. 1 shows a transparent egg carton 10 having a tray 12 and a lid 14hingedly connected thereto for movement between and open condition(FIG. 1) to a closed condition (FIG. 2). The tray 10 has a generallyrectangular peripheral wall 16 having a front edge 18 and a rear edge 20defining an imaginary plane of the tray 22. The tray has a first row 24of a plurality of egg compartments 26 and a second row 28 of a pluralityof egg compartments 26 in parallel spaced relationship to the first row.While it is shown that each of the first and second rows of eggcompartments have six compartments it is contemplated that each rowcould have from as little as two up to twelve or more compartmentsprovided the container has sufficient physical properties to protect theeggs during shipment and handling by a user of the eggs. Each eggcompartment 26 has a generally ovoid shaped wall 30 that extendsdownward below the plane of the tray 22 and is closed by an end wall 32.In one preferred form of the invention, the end wall has an innersurface 34 that extends concave upwardly. A plurality ofcircumferentially spaced and inwardly extending tabs 36 are deformedfrom the wall for engaging an outer surface of an egg. The tabs aregenerally rectangular shaped with rounded ends with the length dimensionoriented parallel to an axis of the compartment. In a preferred form ofthe invention eight tabs are provided and are equally spaced about thecircumference of the wall 30 of the compartment. The tabs contact theshell of an egg to reduce the surface area that the shell is in contactwith the wall 30. By reducing the surface area contact between the walland the egg shell reduces the tendency for the egg to stick to the wallof the compartment and to become damaged upon removal from thecompartment.

FIGS. 1-3 show a plurality of tower elements 40 spaced horizontallyalong a centerline 42 of the tray and extending vertically upwardlyabove the plane of the tray by a first distance. Each tower element 40has four egg contacting surfaces 44 one of each surface associated witha different egg compartment. The egg contacting surfaces 44 are concaveto conform to a portion of an egg that extends above the plane of thetray. Each tower element 40 has a top end 46 that is generally circularand has a flat surface 48 for contacting a bottom surface of the lid 14to protect the egg contents from crushing even upon stacking of othersimilar filled egg cartons on top of the lid. A notch 47 is providedalong a wall connecting each adjacent tower element 40 to provide a ventfor when eggs are inserted into each egg compartment.

A plurality of horizontally-spaced supports 50 are provided along thefront edge 18 of the tray. The supports 50 extend above the plane 22 asecond distance which is less than the first distance. Each of thesupports 50 have two egg contacting surfaces 52 for contacting eggs intwo adjacent egg compartments of the first row 24. The egg contactingsurfaces 52 are generally concave to conform to the shape of an eggplaced in the compartment. The supports 50 have the shape of a truncatedequilateral triangle in horizontal cross-section dimension with atruncated apex 54 pointing inward of the container toward the towerelements 40. In a preferred form of the invention, two of the outermostsupports, those closest to lateral edges 56 of the tray, have atooth-shaped protuberance 58 extending outwardly of the container froman outer surface 60. The tooth-shaped protuberance 58 has an outwardlytapering and downwardly extending surface 62 defining a downwardlyfacing surface 64 with a laterally extending groove 66. The protuberance58 is commonly known as a button tab and is for releasably engaging abutton tab mating surface 68 on the lid 14, as will be discussed ingreater detail below.

As seen in FIG. 1, the center support 70 is segmented with a lowersection 72 and an upper section 74 connected by a tapering middletransition section 76. During closing of the lid, the transition section76 engages a tab mating surface 68 of the lid and guides the lid intoproper alignment for engagement of the lower section 72 with a buttontab mating surface 68 on the lid.

A plurality of horizontally-spaced post elements 80 are positioned alongthe rear edge 20 of the tray each of which has two egg contactingsurfaces 82 for contacting two eggs one of each in adjacent eggcompartments of the second row of egg compartments 26. Each of the postelements 80 have the shape of a truncated equilateral triangle inhorizontal cross-section dimension with a truncated apex 84 pointinginward of the container toward the tower elements 40. Each of the postelements 80 extend vertically upward above the plane 22 of the tray athird distance and terminate in a flat upper surface 86. The thirddistance is less than the second distance.

FIGS. 1 and 3 also show an optional feature of four corner tabs 90 thatextend vertically above the plane 22 of the tray and each has an eggcontacting surface 92 that is generally concave, a rear wall that isgenerally convex 94 and has a flat top surface 96. The corner tabsengage optional compartments in the lid to ensure proper alignment ofthe lid with the tray when in the closed condition and to resistinadvertent opening of the lid.

As best seen in FIGS. 5 and 6, a buttress 98 extends below the plane 22of the tray and between each adjacent egg compartment to provide supportalong the longitudinal dimension of the tray. In a preferred form of theinvention, the buttress extends from about 40% to about 90%, morepreferably from about 45% to about 85% and most preferably from about50% to about 80%, or any range or combination of ranges therein, as faras the end wall 32 extends from the plane 22. The buttress is generallyU-shaped in vertical cross-section dimension and in a preferred form ofthe invention has an optional strut 100 that is generally arcuate shapedand extends upward into the tray and between two legs of the U-shapedbuttress. The strut is to provide support along the latitudinaldimension of the carton.

FIGS. 1-5 show the generally rectangular shaped lid 14 having twohorizontally spaced end walls 102, a front wall 104 and a rear wall 106in parallel spaced relationship, all of which are vertically upstandingand are connected by a horizontally extending top wall 108. The frontwall 104 has three button-tab mating surfaces 68. In another preferredform of the invention only the two outermost button tabs are provided;thus, the center button tab shown is optional. In one preferred form ofthe invention, the two outermost button-tab mating surfaces consist of agenerally rectangular opening 110 through the entire thickness of thefront wall. When the lid is in the closed condition, each of thetooth-shaped protuberances 58 extend through the opening 110 and alateral edge of each tooth engages a vertically extending edge 112 ofthe opening and the groove 66 engages a bottom 114, horizontallyextending edge of the opening to releasably engage the lid. The distancebetween the vertically extending edges 112 is about the same as thedistance between the lateral edges of each tooth they engage to placethe lid under lateral tension to resists inadvertent opening of the lid.The optional middle button-mating surface 68 is rectangular shapedindentation that is dimensioned to interlock with the lower section 72of the center support 70 when the lid is in the closed condition (FIG.2). It should be understood that the button-mating surfaces describedabove are interchangeable and any combination of the same could be used.

At each of the corners 116 of the lid are optional arcuate shapedpockets 118 having a bottom wall 120 for engaging the corner tabs 90 ofthe tray. FIG. 3 also shows several optional strengthening indentations120 deformed from the top wall 108 of the lid—two optionallongitudinally extending indents 122 in registration with a centerlinedrawn through the centers of the first and second rows of eggcompartments 24,26 and four optional lattitudinally extending indents126 forming a line between adjacent tower elements 40. Verticallyextending indents 126 are also provided on the lid front and rear walls104,106 in alignment respectively with the supports 50 and the postelements 80. The lateral end walls of the lid each have two raised areas129 that are in registration with raised areas 130 on the tray lateralwalls to form vents that are in alignment with the center of the firstand second row of egg compartments.

The lid rear wall 106 is hingedly connected to the rear edge of the tray20 with a W-shaped hinge or a box hinge 131 as set forth in U.S. Pat.No. 7,258,234 which is incorporated herein by reference and made a parthereof.

FIGS. 6, 7 a,b show another preferred form of the invention that differsfrom the embodiment shown in FIGS. 1-5 by the provision of a gutter 132that extends from the front edge of the tray 18 and is dimensioned toreleasably interlock with a tab 134 extending from the lid front wall104. The gutter and tab have complementary shapes such as concave andconvex for the parts to fit together and form an interference fit. Alsoprovided on the front edge of the tray 18 is a finger recessed area 136generally centrally located thereon.

One advantage of the present invention is that the transparent,polymeric egg carton has no flap extending from the front edge of thetray. This provides significant savings in terms of material usedwithout diminishing the desirable physical properties of the carton andits ease of use by consumers.

From the foregoing, it will be observed that numerous variations andmodifications may be effected without departing from the spirit andscope of the invention. It is to be understood that no limitation withrespect to the specific apparatus illustrated herein is intended orshould be inferred. It is, of course, intended to cover by the appendedclaims all such modifications as fall within the scope of the claims

We claim:
 1. An egg carton comprising: a tray having a first row of afirst plurality of spaced egg compartments and a second row of a secondplurality of spaced egg compartments, the first row of egg compartmentsbeing disposed in parallel spaced relationship to the second row of eggcompartments; a plurality of spaced tower elements extending along acenterline of the tray and extending vertically from a plane of thetray, each tower element having four egg contacting surfaces; aplurality of spaced post elements extending along a front edge of thetray and extending vertically from a plane of the tray, each postelement having two egg contacting surfaces; and a lid hingedly connectedalong a rear edge of the tray and movable from an open condition to aclosed condition.
 2. The egg carton of claim 1 wherein each of theplurality of post elements is aligned with each of the plurality oftower elements.
 3. The egg carton of claim 1 wherein the first pluralityof egg compartments and the second plurality of egg compartmentscomprises at least two egg compartments.
 4. The egg carton of claim 1wherein the post elements are positioned between adjacent eggcompartments of the first plurality of egg compartments.
 5. The eggcarton of claim 1 wherein one of each of the two egg contacting surfacesof the post elements form a portion of each of two adjacent eggcompartments.
 6. The egg carton of claim 1 further comprising a firstbutton tab on a first post element and a first mating button surface onthe lid, wherein when the egg carton is in the closed condition thefirst button tab is positioned in the first mating button surface toreleasably interlock the lid to the tray.
 7. The egg carton of claim 6wherein the first mating button surface is an indentation in the lid ora through hole in the lid.
 8. The egg carton of claim 6 furthercomprising a second button tab on a second post element and a secondmating button surface on the lid spaced from the first mating buttonsurface, wherein when the egg carton is in the closed condition thesecond button tab is positioned in the second button surface toreleasably interlock the lid to the tray.
 9. The egg carton of claim 8wherein the second mating button surface is an indentation in the lid ora through hole in the lid.
 10. The egg carton of claim 8 furthercomprising a third button tab on a third post element positioned betweenthe first post element and the second post element and a third matingbutton surface on the lid positioned between the first mating buttonsurface and the second mating button surface and wherein when the eggcarton is in the closed condition the third button tab is positioned inthe third mating button surface.
 11. The egg carton of claim 8 whereinthe first button tab comprises a flange extending outwardly from aportion of the first post element and having a downwardly facingsurface.
 12. The egg carton of claim 11 wherein the downwardly facingsurface has a groove dimensioned to releasably retain the first matingtab surface.
 13. The egg carton of claim 1 further comprising aplurality of spaced supports positioned along a rear edge of the traythat extend vertically from a plane of the tray.
 14. The egg carton ofclaim 13 wherein each support of the plurality of supports have two eggcontacting surfaces.
 15. The egg carton of claim 13 wherein one of eachof the plurality of supports is in alignment with one of each of theplurality of tower elements.
 16. The egg carton of claim 13 wherein thesupports are positioned between two adjacent egg compartments of thesecond plurality of egg compartments.
 17. The egg carton of claim 13wherein the tower elements extend a first vertical distance from a planeof the tray, the post elements extend a second vertical distance fromthe plane and the supports extend a third vertical distance wherein thefirst vertical distance is greater than the second vertical distance andthe third vertical distance.
 18. The egg carton of claim 17 wherein thesecond vertical distance is greater than the third vertical distance.19. The egg carton of claim 1 further comprising a gutter extending fromthe front edge of the tray and dimensioned to releasably retain aportion of the lid when in the closed condition.